Terence McCann

All the others OK?

Speaking of recalls Mike, do you have any information/links listing recalls (such as HVAC)? I know you post the recalls as they come up but do you store them in a folder somewhere for easy access? TIA

It was vinyl Mike. Thanks for the replies, wasn't sure if it was a code thing or not.

Did a detached condo that was built in 2002. I pulled the siding back to have a look and noticed that it was OSB only, no Tyvex© noted. Is house wrap mandatory or just good building pratice? Btw, Happy T-Day to all.

Hi Randy, What Jeff said, as well as the links Mike posted, are good guides. The problem is that when things start to go awry it takes a technician, with all the tools and gadgets, to accurately troubleshoot the system. There are so many nuances with troubleshooting systems you'd really have to attend a tech school to get a basic handle on the process. I don't mean to sound condescending however, there are so many variables with systems. After spending 27 years in the HVAC/R /P trade a few things managed to filter into my thick head (common sense not being one of them).

Jim, Did you check the liquid line before or after the liquid line dryer? The reason I ask is that it is possible for the liquid line dryer to plug up. This usually happens after a compressor change-out due to a burn. The liquid line dryer now starts to act like a TXV of sorts. Moisture in the system will also give this affect. What's weird with moisture is that the system will start and run OK for a while but then you will start to see things, like your seeing, as the moisture start to freeze and restrict certain areas. In any case it is hard (if not impossible) to troubleshoot with out gauges and temperature probes which, are outside the scope.

With an outdoor ambient of 61 and indoor of 71 there was little if any load on the machine. The liquid line had a ton of sub-cooling so a "cool to the touch" temperature is to be expected. At 60° outside the head pressure on the machine would be (assuming a 30° rise and the unit is R-22) 168#. Toss in 10° plus of sub-cooling and you have a liquid line temperature of 75° or so, cool to the touch. Normal liquid line temp is around 105° give or take. If it was a newer, high efficiency unit with an oversized condenser the the liquid line temperature will be even cooler. The suction line being warmer than normal might be of concern however, if I were checking this unit, in these temps, I would tell my client that I just want to make sure it runs and that I can not properly test the unit in these temperatures.

Hi Jim, What was the outdoor temperature? What was the indoor temperature? Any icing of the suction line at the condensing unit or by the evaporator? How many ton was the unit? I can advise on line set size if I know the tonnage. Did you trace the lines out? It's damn near impossible to reverse the connections as the tech would really have to go out of their way to make up special fittings to reverse connections. Assuming that the lines were correct: A cool liquid line and a warmer suction line indicates a low freon charge. If the outdoor temperature was very cool you will have a cooler than normal liquid line as well. With regards to the delta T across the evap, 19° is spot on however, was the filter very dirty? Was the evap fan running on low speed vs high? You can get a good delta T with poor air flow even though the charge may be low. Inadequate return air? Supply ducts closed?

Jim, I'm not sure I follow what their trying to accomplish. If it were true 3-phase you would have 3 wires coming into the top lugs and no need to double back through a breaker. If there are only two wires coming into the top then it's a 220 single phase service however, if their energizing the third bus with one of the legs of the 220 single phase, by doubling back through the breaker, it wouldn't make it 3 phase. It would be a convoluted 220v single phase panel. Plus the main breaker appears to be a single phase 100AMP. What am I not seeing here?

Hello Charles: You could also go on to say the septic tank wasn't inspected due to the fact that there isn't one. The private well water system wasn't inspected due to the fact that the isn't one. The garage wasn't inspected due to the fact that there isn't one. I didn't inspect the oil fired furnace due to the fact that it's an all gas home, ad nauseum. If you stop to think about what you're disclaiming it's really absurd and when you say it out loud to yourself, you have to laugh. Chad is absolutely correct.

Amen

Hi Jim: Google Carrier VVT or Trane VariTrac for more info. Locate your local Trane or Carrier dealer and request some brochures on the various systems.

Great site!

Older furnaces had a bi-metal combination fan-hi limit switch. As the furnace would heat up the bi-metal would twist and thereby making a set of contacts to turn on the furnace blower at 150 degrees and to shut of the gas valve if the bonnet temperature exceeded 200 degrees. When the gas valve shut off the bi-metal would unwind and shut off the blower at 100 degrees. The newer furnaces are controlled by solid state time delays. If yours has circuit boards one of them will need replacement.

That's a possibility however, a true zoned system usually has t-stats to control the dampers to their zone (and are allowed to initiate a call for clg & htg). As these zones cut back the bypass damper opens up due to a signal from static pressure control. Then, as the zones cut back, the Delta T across the evaporator really increases so they have a low-limit t-stat to shut off the unit to prevent liquid slugging. Perhaps Jim could chime back in with a little better explanation of the zoned system and if there is a bypass damper or not. I've seen some zoned systems that do not have a bypass damper as it follows the fan curve to achieve the same thing however, this was in commercial office bldgs. It would also help to know the return air vs the supply air temperatures. A cheapo sling psychrometer would be beneficial as well to measure RH in numerous areas of the home as well as the crawl space. Other question would be, is the unit bringing in any non-conditioned outside air, what was the outdoor ambient temperature and humidity at the time? Obviously these are outside the scope but it helps with understanding the systems better.

Rough rule of thumb is 600 square feet for a ton of cooling (400 per ton in commercial bldgs). A Carrier model 25HPA324300 (*might be a 2.5 ton unit). A flat 2 ton unit seems small for this home. Having said that heat load calcs should be done to be 100% sure. If the humidity was high then temperature should have been as well if the unit was way undersized. If the unit is oversized you get a problem with humidity being to high but temperatures are OK (cold and clammy). Downsizing the condenser is OK to have the unit run longer thereby removing more humidity but again, it has to be big enough to keep the space cool as well. Lack of refrigerant could cause this problem but then you would see ice and the humidity and temperature would be high. Was all the supply ductwork blowing 5x degree supply air and did it have enough return air? Punt and have another HVAC company check all calculations.

I'm in business. I'm in business to make money - period. I will market my company to anyone that gives me the opportunity - period. To not do so would be comparable to Target closing it's doors to anyone over 50 years old and anyone under 40 years old. While this may not be a popular stance I do what I have to do to keep my company afloat and profitable. I was in a seminar last year and Mark Cramer was one of the speakers. He stated that he has coloring books & crayons, with his companies name on them, and that he drops them off at realtors offices. Smart guy. The other thing to keep in mind is that if a realtor only uses you once you have had the opportunity to impress your client (which you didn't have prior to). That's where the best referrals come from.

Well, found a repair center about 40 miles away. Drove out there and they put a new switch in free of charge. I have a backup Mag-Lite but I really hate to part with the Stinger, what a great flashlight.

Has anyone tried to replace the thumb switch on this flashlight? Mine keeps getting stuck in the on position.

I have albeit a while ago. I found that you had to repeat yourself, sometimes alot, to get one word in like Finger, Fiiiinnnnnger, Finger, ah (#*^ it. They may have gotten better.

Getting back to this for one more question. How many do a load calc when needed?

Maybe I'll check with a few of the local municipalities. Perhaps when pulling permits they wanted to see the service upgraded to 100 AMP. Wish I could remember where I heard that. Out of all the things I lost I miss my mind the most.

In older homes that have 60 AMP service and have had air conditioning installed I always recommend upgrading the service 100 Amp minimum. Also, all the years that I was in the trade it was always a given however, does anyone have documentation substantiating this?

I never run with scissors nor do I stick my tongue into electrical outlets, well, once back in the 70's after drinking some Kool-Aid® but that's another story.

Hey Les, I've never seen these in my travels but it sounds like a dirt (no pun intened) cheap fix.